This specification relates to digital data processing, and particularly to computer-implemented search services.
Query suggestion is a search service that helps users reformulate queries to better describe their information needs and reduce the time needed to find information that satisfies their needs. Search services provide search query suggestions as alternatives to search queries input by the users. For example, a search engine can provide a query input field that receives an input search query. In response to receiving search query terms input in the query input field, a search service can provide to the user search query suggestions for the input search query terms. A user can select a search query suggestion for use as a search query.
Conventional search services provide search query suggestions that are particular to a correlation measure used by the search service that generated the search query suggestions. For example, some correlation measures are based on search results returned by queries, others are based on temporal usage patterns. Some conventional search services provide query suggestions that are specifically directed at searching a particular type of resource, for example, images, videos, or web pages. Query suggestions provided based on one correlation measure usually differ from query suggestions provided based on another correlation measure.